Joining operations in document oriented databases

ABSTRACT

An approach for joining operations on document-oriented databases. The approach consists of receiving database identifiers, common attributes and results attributes for core and target databases being joined. Common attributes are searched for in the databases. The searches performed include string, expansive, character and nested. Common attribute join conflicts are identified and input is received to resolve attribute join conflicts. Resolved join conflicts are updated in a join substitution database for subsequent use and joined data results are output to virtual table(s).

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of joining tablesin database queries, and more particularly, to the joining of fieldsthat are similar in document-oriented databases.

Join operations on relational databases are useful to extract therequired data that spreads across multiple normalized databases. Toperform join operation, a common attribute or field is selected in thedatabases of interest and used to create a virtual table with desiredfield values from the joined databases. Unlike relational databases,non-relational database join operations generally do not share standarddatabase schema definitions. Non-relational databases, known asdocument-oriented or ‘NoSQL’ databases have database schemascharacterized as ‘dynamic’ and are often nested or hierarchicallydefined. NoSQL queries often only access fields that have the relateddocument schema as joining data tables is established using exactmatching of common field names between documents.

SUMMARY

As disclosed herein, a method for joining operations ondocument-oriented databases, the method comprising: receiving a databaseidentifier for each of a core database and a plurality of targetdatabases to be joined, one or more common attributes and one or moreresults attributes; searching for the one or more common attributes inthe core database and the plurality of target databases, wherein thesearch comprises at least one of one or more of a string search, aexpansive search, a character search, and a nested search; identifyingone or more common attribute join conflicts; receiving input to resolvethe one or more common attribute join conflicts; storing a one or morecommon attribute join conflict resolution in a one or more joinsubstitution data store and outputting one or more virtual table whereinthe one or more virtual table comprises combined join results based onthe one or more common attributes and the one or more results attributesfrom the core database and the plurality of target databases. A computersystem and a computer program product corresponding to the above methodare also disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating a computingenvironment, in accordance with an embodiment of the present invention;

FIG. 2A, B depicts sample JavaScript Object Notation (JSON) databasesfor an example joining operation, in accordance with an embodiment ofthe present invention;

FIG. 3 is a flowchart depicting join manager logic flow, in accordancewith an embodiment of the present invention; and

FIG. 4 depicts a block diagram of components of the server and/or thecomputing device, in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION

Embodiments of the present invention provide systems, methods andcomputer program products for performing join operations indocument-oriented databases where database schema definitions are notmatching and/or when field names differ between documents. The approachprovided, supports joining of inexact attribute names at equal ordifferent levels in nested document-oriented structures.

Embodiments of the present invention will now be described in detailwith reference to the figures. It should be noted that, references inthe specification to “an exemplary embodiment,” “other embodiments,”etc., indicate that the embodiment described may include a particularfeature, structure, or characteristic, but every embodiment may notnecessarily include the particular feature, structure, orcharacteristic. Moreover, such phrases are not necessarily referring tothe same embodiment. Further, when a particular feature, structure, orcharacteristic is described in connection with an embodiment, it issubmitted that it is within the knowledge of one skilled in the art toaffect such feature, structure, or characteristic in connection withother embodiments whether or not explicitly described.

FIG. 1 is a functional block diagram of computing environment 100, inaccordance with an embodiment of the present invention. Computingenvironment 100 comprises communication device 110, and computer system120, interconnected via network 140. Communication device 110 andcomputer system 120 can be desktop computers, laptop computers,specialized computer servers, or the like. In certain embodiments,communication device 110 and computer system 120 represent computersystems utilizing clustered computers and components acting as a singlepool of seamless resources via network 140. For example, suchembodiments can be used in data center, cloud computing, storage areanetwork (SAN), and network attached storage (NAS) applications. Ingeneral, communication device 110 and computer system 120 arerepresentative of any electronic devices, or combination of electronicdevices, capable of executing computer readable program instructions, asdescribed in detail with regard to FIG. 4.

Network 140 can be, for example, a local area network (LAN), a wide areanetwork (WAN) such as the Internet, or a combination of the two, andinclude wired, wireless, or fiber optic connections. In general, network140 can be any combination of connections and protocols that willsupport communications between communication device 110 and computersystem 120, in accordance with an embodiment of the present invention.

Communication device 110 comprises application(s) 112. Application(s)112 includes at least one of any application that accesses informationon computer system 120 for the purpose of retrieving or managing datafrom one or more document-oriented database(s).

In one embodiment of the present invention, computer system 120comprises join manager 122 and document database 136. Join manager 122comprises user interface 124, join creator 126, expansion terms store128, conflict processor 130 and join substitution store 132. Joinmanager 122 further comprises any combination of commercial or customsoftware products associated with operating and maintaining join manager122. It should be noted that, join manager 122 can be implemented as anApplication Program Interface (API), a program module, a stand-aloneprogram or other device. Further, join manager 122 can be implemented asan integrated or distributed application.

In one embodiment of the present invention, user interface 124 can be aplurality of user interfaces 124 within join manager 122. User interface124 receives input to initiate a join operation, outputs commonattribute join conflicts, common attribute join conflict resolutionactions and receives user action choices to resolve common attributejoin conflict(s). User interface 124 receives and outputs data inpredefined formats and content based on implementation needs.

Join creator 126 processes input received from user interface 124 tosearch document database 136 for common and closely matching attributesto complete a table and/or database join. Embodiments of the presentinvention comprises at least one of, string search (exact match),expansive search, character search and nested search. Results of eachsearch can produce multiple combinations to join attributes and joincreator 126 identifies those occurrences as common attribute joinconflicts. Join creator 126 sends common attribute join conflicts towardconflict processor 130 for resolution. When conflict processor 130resolves common attribute join conflicts, join creator 126 retrievesjoined data from document database 136 based on results attributesspecified from user interface 124. Join creator 126 produces a virtualtable of results based on attributes requested from user interface 124.

In one embodiment of the present invention, expansion terms store 128can be a plurality of expansion terms stores 128 within join manager122. In other embodiments of the present invention, expansion termsstore 128 can be a combination of expansion terms stores 128 distributedbetween communication device 110 and computer system 120. Expansionterms store 128 contains a list of synonyms to replace search attributesused during a join. For example, an attribute name of ‘PAN’ can also be‘Permanent Account Number’ in other database instances. Join creator 126uses expansion terms store 128 to conduct expansive and nested searches.It should be noted that a user can edit (add, remove, change) expansionterms store 128 and administrative function is based on implementationneeds.

In one embodiment of the present invention, conflict processor 130 canbe a plurality of conflict processors 130 within join manager 122.Conflict processor 130 creates a list of common attribute join conflictsidentified by join creator 126. Conflict processor 130 searches joinsubstitution store 132 for existing similar joins conflicts resolutionactions, combines matching common attribute join conflicts and sends thelist toward user interface 124. When a user chooses actions to resolvecommon attribute join conflicts provided by user interface 124, conflictprocessor 130 records those actions to join substitution store 132. Inan embodiment of the present invention, when a single conflict actionmatches an existing action in join substitution store 132, the existingjoin can be automatically selected without user interface 124interaction.

In one embodiment of the present invention, join substitution store 132can be a plurality of join substitution stores 132 within join manager122. Join substitution store 132 contains a history of common attributejoin conflict actions taken. Conflict processor 130 uses joinsubstitution store 132 to retrieve common attribute join conflictresolution actions that match common attribute join conflicts processedby conflict processor 130. For example, join substitution store 132could contain a former join depicting“table2A.office_number=table2B.phone_number.office_number.” Theaforementioned example join can be used as a join solution during joinconflict resolution.

FIG. 2A depicts a sample JavaScript Object Notation (JSON) database foran example joining operation, in accordance with an embodiment of thepresent invention. It should be noted that embodiments of the presentinvention are described with reference to JSON but embodiments of thepresent invention are not limited to JSON. JSON data structure is one ofmany data standards that describes document-oriented database datastructure on which embodiments of the present invention operate. TheJSON database A 200 represents one aspect of JSON basic schema that canbe contained in document database 136. The JSON database in FIG. 2A is asingle level data record encapsulated by curly brackets “{ }”. Fields202 Firstname, 204 lastname, 206 address, 208 office_number, 210residence_number and 212 permanent_account_number are field value pairs.Each field value pair is delimited by a colon “:” and each unique fieldvalue pair is separated by a comma “,”. Delimiters and separatorcharacters are predetermined by each specific document database 136 datastandard. It should be noted that field value pair is a term used todescribe JSON data construct whereas a ‘field’ can be identified as an‘attribute’.

FIG. 2B depicts a sample nested JSON database for an example joiningoperation, in accordance with an embodiment of the present invention.The JSON database B 220 represents one aspect of JSON nested schema thatcan be contained in document database 136. The JSON database in FIG. 2Bis a multiple level data record where each field value pair level isencapsulated by curly brackets “{ }”. Fields 222 name and 226phone_number are nested groupings of more specific field values pair.Fields 224 address and field 230 pan are field value pairs at the toplevel of the hierarchical data structure. Field 228 home_number is anested field value pair at a first level of 226 phone_number.

Embodiments of the present invention will use string, expansive,character, and nested search to match fields depicted in FIG. 2A withFIG. 2B. Fields 202 Firstname and 204 Lastname match with field namesidentified within nested field 222 name using a nested search. Note,firstname is in lower case in field 222 name where field 202 Firstnameis mixed case. In this example, a character search can resolve a matchfor field 202 within a nested search. Likewise, field 204 Lastname inmixed case can use character or expansive search to match field 2221_name (short form for last name). Field 206 address can match field 224address using exact match string search. Field 208 office_number and 210residence_number can match to fields nested in field 226 phone_numbernoting that a character or expansive search can match field 210residence_number with field 228 home_number. Field 212permanent_account_number can match field 230 pan using expansive search.

FIG. 3 is a flowchart depicting join manager logic flow, in accordancewith an embodiment of the present invention. Step 302 receive input inflow diagram 300 join manager operation is an interfacing function thatcaptures requests to process joining of database fields. Inputparameters are received such as, but not limited to, database name(s),common attribute(s) to search on and results attribute(s) to return froman application(s) 112 join request. It should be noted that assignmentof a database as core and a database as target are predetermined basedon input parameters from step 302 receive input. A core database is theprimary database that a target database is joined. Further, the coredatabase common attribute(s) names are specified exactly from step 302receive input whereas target database common attribute(s) names can beinexact and assist join searching.

Step 304 select db reads each database structure to begin a join basedon the provided database identifiers from step 302 receive input.

Step 306 search common attr performs a string search to find an exactattribute name match between the core database and one or more targetdatabases using the common attribute(s) based on the providedidentifiers from step 302 receive input. For example, target field 224address (FIG. 2B) exactly matches core table field 206 address (FIG.2A).

Step 308 attr found is a verification that core and target databasetables are joined properly. If a join was not completed, (e.g., fieldattribute was not found in the target database) then other searchmethods are executed. Other search methods comprise expansive, characterand nested search. For each search method conducted, step 308 attr foundchecks respective search results to determine if another method can beused. It should be noted that processing sequence and/or execution ofall search methods is not mandatory. It should be further noted, someembodiments of the present invention could be optimized by limiting howmany search methods are executed to find potential join attributes.

Step 310 perform expansive search is executed when step 308 attr foundis ‘no’. Step 310 perform expansive search searches expansion termsstore 128 for alternate attribute name(s) of the common attribute(s)provided from step 302 receive input. The common attribute is expandedif there is an existing expansive form for that attribute in expansionterms store 128 and a string search is conducted, similar to step 306search common attr. For example, core table field 212permanent_account_number (FIG. 2A) can be found in expansion terms store128 as target field 230 pan (FIG. 2B). Note, known expansion terms canbe predetermined and/or updated/added by a user. If there are more thanone matching attributes found, then a common attribute join conflict isnoted. Step 310 perform expansive search results are sent toward step308 attr found.

Step 312 perform char search is executed when step 308 attr found is‘no’. Step 312 perform char search searches for partial matches of thecommon attribute(s) provided from step 302 receive input. The commonattribute is searched for a partial string commonality with otherattributes in the database. The partial search is performed to find aclosely matching attribute. For example, target nested field 222 name(FIG. 2B) contains l_name and character search can identify a match withbase field 204 lastname (FIG. 2A). If there are more than one matchingattributes found, then a common attribute join conflict is noted. Step312 perform char search results are sent toward step 308 attr found.

Step 314 perform nested search is executed when step 308 attr found is‘no’. Step 314 perform nested search traverses each level of thedatabase schema tree and progressively conducts step 306 search commonattr, step 310 perform expansive search and step 312 perform char searchto find common attribute matches. For example, target field 228home_number (FIG. 2B) can match core field 210 residence_number (FIG.2A) using step 310 perform expansive search within step 314 performnested search. If there are more than one matching attributes found,then a common attribute join conflict is noted. Step 314 perform nestedsearch results are sent toward step 308 attr found.

When Step 308 attr found is ‘yes’, then step 316 attr conflictdetermines if more than one matching attributes was noted as a commonattribute join conflict based on results of at least one of, step 310perform expansive search, step 312 perform char search and step 314perform nested search processing. If step 316 attr conflict is ‘yes’,then step 318 user select is conducted. If step 316 attr conflict is‘no’, then step 320 output virtual table is conducted.

Step 318 user select presents noted common attribute join conflicts to auser for resolution action. In addition, step 318 user select searchesjoin substitution store 132 for historic common attribute join conflictresolution actions that can exist for each noted common attribute joinconflict. The historic common attribute join conflict resolution actionscan be presented to the user with the list of noted common attributejoin conflicts for the user to select an action choice and resolve eachnoted common attribute join conflict. Once the user has resolved eachcommon attribute join conflict, step 318 user select stores the commonattribute join conflict resolution action decision in join substitutionstore 132 and step 320 output virtual table is conducted. It should benoted, in some embodiments of the present invention, a single commonattribute join conflict could have a closely matching attribute. In thiscase, the closely matching attribute can be selected automatically bystep 318 user select logic and the join operation can continue withoutthe user selection of a resolution action.

Step 320 output virtual table is the results set of the joined dataretrieved from document database 136 using core database attributes andthe replaced target database attributes in join substitution store 132.Join substitution store 132 is used to replace joining attributesresulting from at least one of the completed string, expansive,character and nested searches. Application(s) 112 requesting joinedoutput from join manager 122 is provided output by a predeterminedmethod and format based on implementation needs.

FIG. 4 depicts a block diagram of components of communication device 110and computer system 120 in accordance with an illustrative embodiment ofthe present invention. It should be appreciated that FIG. 4 providesonly an illustration of one implementation and does not imply anylimitations with regard to the environments in which differentembodiments may be implemented. Many modifications to the depictedenvironment may be made.

Computer system 400 includes communications fabric 402, which providescommunications between computer processor(s) 404, memory 406, persistentstorage 408, communications unit 410, and input/output (I/O)interface(s) 412. Communications fabric 402 can be implemented with anyarchitecture designed for passing data and/or control informationbetween processors (such as microprocessors, communications and networkprocessors, etc.), system memory, peripheral devices, and any otherhardware components within a system. For example, communications fabric402 can be implemented with one or more buses.

Computer system 400 includes processors 404, cache 416, memory 406,persistent storage 408, communications unit 410, input/output (I/O)interface(s) 412 and communications fabric 402. Communications fabric402 provides communications between cache 416, memory 406, persistentstorage 408, communications unit 410, and input/output (I/O)interface(s) 412. Communications fabric 402 can be implemented with anyarchitecture designed for passing data and/or control informationbetween processors (such as microprocessors, communications and networkprocessors, etc.), system memory, peripheral devices, and any otherhardware components within a system. For example, communications fabric402 can be implemented with one or more buses or a crossbar switch.

Memory 406 and persistent storage 408 are computer readable storagemedia. In this embodiment, memory 406 includes random access memory(RAM). In general, memory 406 can include any suitable volatile ornon-volatile computer readable storage media. Cache 416 is a fast memorythat enhances the performance of processors 404 by holding recentlyaccessed data, and data near recently accessed data, from memory 406.

Program instructions and data used to practice embodiments of thepresent invention may be stored in persistent storage 408 and in memory406 for execution by one or more of the respective processors 404 viacache 416. In an embodiment, persistent storage 408 includes a magnetichard disk drive. Alternatively, or in addition to a magnetic hard diskdrive, persistent storage 408 can include a solid state hard drive, asemiconductor storage device, read-only memory (ROM), erasableprogrammable read-only memory (EPROM), flash memory, or any othercomputer readable storage media that is capable of storing programinstructions or digital information.

The media used by persistent storage 408 may also be removable. Forexample, a removable hard drive may be used for persistent storage 408.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer readable storage medium that is also part of persistent storage408.

Communications unit 410, in these examples, provides for communicationswith other data processing systems or devices. In these examples,communications unit 410 includes one or more network interface cards.Communications unit 410 may provide communications through the use ofeither or both physical and wireless communications links. Programinstructions and data used to practice embodiments of the presentinvention may be downloaded to persistent storage 408 throughcommunications unit 410.

I/O interface(s) 412 allows for input and output of data with otherdevices that may be connected to each computer system. For example, I/Ointerface 412 may provide a connection to external devices 418 such as akeyboard, keypad, a touch screen, and/or some other suitable inputdevice. External devices 418 can also include portable computer readablestorage media such as, for example, thumb drives, portable optical ormagnetic disks, and memory cards. Software and data used to practiceembodiments of the present invention can be stored on such portablecomputer readable storage media and can be loaded onto persistentstorage 408 via I/O interface(s) 412. I/O interface(s) 412 also connectto display 420.

Display 420 provides a mechanism to display data to a user and may be,for example, a computer monitor.

The programs described herein are identified based upon the applicationfor which they are implemented in a specific embodiment of theinvention. However, it should be appreciated that any particular programnomenclature herein is used merely for convenience, and thus theinvention should not be limited to use solely in any specificapplication identified and/or implied by such nomenclature.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

What is claimed is:
 1. A method for joining operations ondocument-oriented databases, the method comprising: receiving aplurality of database identifiers for each of a core database and aplurality of target databases to be joined, one or more commonattributes and one or more results attributes; searching for the one ormore common attributes in the core database and the plurality of targetdatabases, wherein the search comprises at least one of one or more of astring search, a expansive search, a character search, and a nestedsearch; identifying one or more common attribute join conflicts;receiving input to resolve the one or more common attribute joinconflicts wherein the input is a user selected resolution action;storing a one or more common attribute join conflict resolution in a oneor more join substitution data store; and outputting one or more virtualtables, wherein the one or more virtual tables comprises combined joinresults incorporating the one or more common attribute join conflictresolution, and the one or more results attributes from the coredatabase and the plurality of target databases.
 2. The method of claim1, wherein receiving input further comprising: creating one or morechoices for each of the one or more common attribute join conflicts;searching for one or more matching join conflict resolutions in the oneor more join substitution data store based on each of the one or morecommon attribute join conflicts; combining the one or more choices andthe one or more matching join conflict resolutions to create a one ormore conflict resolution choices; and outputting the one or moreconflict resolution choices for one or more conflict resolutionselection.
 3. The method of claim 1, wherein the expansive searchreplaces one of the one or more common attributes based on apredetermined one or more expansion terms data store.
 4. The method ofclaim 1, wherein searching replaces one of the one or more commonattributes based on the one or more join substitution data store.
 5. Themethod of claim 1, wherein the nested search traverses each of the coredatabase and the plurality of target databases schema levels of each ofthe core database and the plurality of target databases, using at leastone of a one or more of the string search, the expansive search and thecharacter search.
 6. The method of claim 1, wherein the one or more joinsubstitution data stores are maintained by received input to resolve theone or more common attribute join conflicts.
 7. The method of claim 1,wherein the one or more expansion terms data store is maintained by auser.
 8. A computer program product for joining operations ondocument-oriented databases, the computer program product comprising:one or more computer readable storage media and program instructionsstored on the one or more computer readable storage media, the programinstructions comprising: program instructions to, receive a plurality ofdatabase identifiers for each of a core database and a plurality oftarget databases to be joined, one or more common attributes and one ormore results attributes; program instructions to, search for the one ormore common attributes in the core database and the plurality of targetdatabases, wherein the search comprises at least one of one or more of astring search, a expansive search, a character search, and a nestedsearch; program instructions to, identify one or more common attributejoin conflicts; program instructions to, receive input to resolve theone or more common attribute join conflicts wherein the input is a userselected resolution action; program instructions to, store a one or morecommon attribute join conflict resolution in a one or more joinsubstitution data store; and program instructions to, output one or morevirtual tables, wherein the one or more virtual tables comprisescombined join results incorporating the one or more common attributejoin conflict resolution, the one or more results attributes from thecore database and the plurality of target databases.
 9. The computerprogram product of claim 8, wherein receiving input further comprising:program instructions to, create one or more choices for each of the oneor more common attribute join conflicts; program instructions to, searchfor one or more matching join conflict resolutions in the one or morejoin substitution data store based on each of the one or more commonattribute join conflicts; program instructions to, combine the one ormore choices and the one or more matching join conflict resolutions tocreate a one or more conflict resolution choices; and programinstructions to, output the one or more conflict resolution choices forone or more conflict resolution selection.
 10. The computer programproduct of claim 8, wherein the expansive search replaces one of the oneor more common attributes based on a predetermined one or more expansionterms data store.
 11. The computer program product of claim 8, whereinsearching replaces one of the one or more common attributes based on theone or more join substitution data store.
 12. The computer programproduct of claim 8, wherein the nested search traverses each of the coredatabase and the plurality of target databases schema levels of each ofthe core database and the plurality of target databases, using at leastone of a one or more of the string search, the expansive search and thecharacter search.
 13. The computer program product of claim 8, whereinthe one or more join substitution data stores are maintained by receivedinput to resolve the one or more common attribute join conflicts. 14.The computer program product of claim 8, wherein the one or moreexpansion terms data store is maintained by a user.
 15. A computersystem for joining operations on document-oriented databases, thecomputer system comprising: one or more computer processors; one or morecomputer readable storage media; program instructions stored on the oneor more computer readable storage media for execution by at least one ofthe one or more computer processors, the program instructionscomprising: program instructions to, receive a plurality of databaseidentifiers for each of a core database and a plurality of targetdatabases to be joined, one or more common attributes and one or moreresults attributes; program instructions to, search for the one or morecommon attributes in the core database and the plurality of targetdatabases, wherein the search comprises at least one of one or more of astring search, a expansive search, a character search, and a nestedsearch; program instructions to, identify one or more common attributejoin conflicts; program instructions to, receive input to resolve theone or more common attribute join conflicts wherein the input is a userselected resolution action; program instructions to, store a one or morecommon attribute join conflict resolution in a one or more joinsubstitution data store; and program instructions to, output one or morevirtual tables wherein the one or more virtual tables comprises combinedjoin results incorporating the one or more common attribute joinconflict resolution, the one or more results attributes from the coredatabase and the plurality of target databases.
 16. The computer systemof claim 15, wherein receiving input further comprising: programinstructions to, create one or more choices for each of the one or morecommon attribute join conflicts; program instructions to, search for oneor more matching join conflict resolutions in the one or more joinsubstitution data store based on each of the one or more commonattribute join conflicts; program instructions to, combine the one ormore choices and the one or more matching join conflict resolutions tocreate a one or more conflict resolution choices; and programinstructions to, output the one or more conflict resolution choices forone or more conflict resolution selection.
 17. The computer system ofclaim 15, wherein the expansive search replaces one of the one or morecommon attributes based on a predetermined one or more expansion termsdata store.
 18. The computer system of claim 15, wherein searchingreplaces one of the one or more common attributes based on the one ormore join substitution data store.
 19. The computer system of claim 15,wherein the nested search traverses each of the core database and theplurality of target databases schema levels of each of the core databaseand the plurality of target databases, using at least one of a one ormore of the string search, the expansive search and the charactersearch.
 20. The computer system of claim 15, wherein the one or morejoin substitution data stores are maintained by received input toresolve the one or more common attribute join conflicts.